JP2008022391A - Packet transfer apparatus and communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent delay in transfer of speech communication packet in the network including L2SW under the setting of the uplink VLAN. <P>SOLUTION: The packet transfer apparatus (1) stores, in the process to establish a session among the terminals (5) connected, correspondence relationship between the information for identifying an originating side terminal (5-1) and a terminating side terminal (5-2) and connection port (user connection information) to a table. For example, an destination IP address, a transmission source IP address, a destination port number, a transmission source port number, and a connection port, etc. are stored in the table by snooping SIP messages of the session control packets communicated among the terminals (5). When the RTP packet as the speed data is received after establishment of session, the packet transfer apparatus (1) returns the same packet therefrom or transfers the packet to an uplink port in accordance with the table explained above. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a packet transfer apparatus and a communication system, and in particular, a transfer delay time when performing VoIP communication via a virtual communication path between SIP apparatus terminals connected to the same packet transfer apparatus of an Ethernet (registered trademark) network. The present invention relates to a packet transfer apparatus (L2SW) and a communication system effective for reduction.

In recent years, managers in apartment houses, condominiums, hotels, and tenant buildings have subscribed to high-speed Internet access services, and the above managers share with each user via a LAN such as Ethernet (registered trademark). And providing a shared Internet connection service to be used.
In the shared Internet connection service, each user does not need to individually connect to the ISP and can be easily used. However, the shared Internet connection service is connected by a LAN such as Ethernet (registered trademark), and can be used from a certain user terminal. The broadcast packet is transmitted to all user terminals via the L2SW. For this reason, by setting up an uplink VLAN for permitting packet transfer with a specific port (uplink port) connected to an ISP, for example, for a port connected to each user terminal in the L2SW, a broadcast packet is set. Is not transferred to other users (ports other than uplink ports), and layer 2 communication between ports connecting users can be prevented. For packets other than broadcast packets, the IP packet redirected from the uplink port by the uplink VLAN setting is routed back by the upper router, thereby realizing communication between users in the same domain.

  On the other hand, in the field of IP telephones, VoIP (Voice over IP) technology for transmitting voice in IP packets is known. In VoIP, a virtual communication path (session) is established between terminals before the start of communication, and an IP packet including voice data is transferred on the communication path. Establishment and disconnection of a session between terminals is performed according to a session control protocol.

IETF (Internet Engineering Task Force) has specified SIP (Session Initiation Protocol: RFC3261) and RTP (Real-time Transport Protocol) suitable for VoIP as session control protocols in IP multimedia communication (for example, non-patented protocol). References 1 and 3). SIP is an application protocol that uses a transport mechanism such as TCP (Transmission Control Protocol) or UDP (User Datagram Protocol). SIP is a text-based protocol, and a SIP message is composed of a header part that carries request or response information and a message body that describes session contents. For example, SDP (Session Description Protocol, see Non-Patent Document 2) is applied to the description of the session, and the communication partner is identified by the SIP URI (Uniform Resource Identifier). In VoIP, RTP is used to transmit encoded voice data.
The operation mode of the SIP server includes a proxy mode in which a session establishment (call setting) request between terminals is mediated by the SIP server, and the calling terminal acquires information on the called terminal from the SIP server, and directly with the called terminal. There is a Redirect mode for communication.

SIP (Session Initiation Protocol), RFC3261 SDP (Session Description Protocol), RFC2327 RTP (Real-time Transport Protocol), RFC1889

  When a voice call is realized on an IP network such as the Internet or an intranet, the voice is converted into an IP packet and transferred to the IP network. In an IP network, many users share and there are a large amount of RTP packets and non-RTP packets. Even if there is no particular inconvenience when the network is free, a delay may occur due to interruption of other packets at the time of congestion. Further, in a network in which L2SWs configured with uplink VLANs are configured in multiple stages, the transfer delay increases as the number of devices that relay IP packets increases, and voice delay becomes a problem.

  In view of the above points, the present invention provides a packet transfer apparatus that prevents a voice data transfer delay when a voice call is made between terminal apparatuses connected to a packet transfer apparatus set up in an uplink VLAN in the same domain. The purpose is to provide. Another object of the present invention is to prevent quality deterioration due to transfer delay of audio data. An object of the present invention is to achieve both security ensuring by applying an uplink VLAN and reduction in transfer delay.

  The present invention registers correspondence information between connection ports and information that can identify between terminal devices from SIP messages in the session establishment process, between the terminal devices connected to the same packet transfer device, in the packet transfer device. One of the purposes is to enable RTP communication via a folded virtual communication path. Another object of the present invention is to reduce the packet transfer delay time. Another object of the present invention is to register priorities of different protocols in a table and enable transfer with priority on RTP communication.

  In order to achieve the above object, the packet transfer apparatus can identify the originating SIP apparatus terminal and the called SIP apparatus terminal in the process of establishing a session between the SIP apparatus terminals connected to the same packet transfer apparatus ( A device management table and a user connection management table for storing the correspondence between the identification information) and the connection ports. One of the features is that when an RTP packet, which is voice data, is received after the session is established, the packet transfer apparatus performs loopback transfer according to the above table.

  This packet transfer apparatus snooping a SIP message of a session control packet communicated between SIP apparatus terminals (SIP snooping) to identify information specifying the SIP apparatus terminal, for example, a destination IP address, a source IP address, a destination One of the features is that the correspondence between the port number, the transmission source port number, and the connection port is stored in the device management table and the user connection management table.

  After the session is established, the destination IP address, the source IP address, the header information of the RTP packet received from the originating SIP device terminal and the terminating SIP device terminal, and the user connection information of the user connection management table stored in the session connection process, One of the features is that the destination port number and the source port number are checked, RTP packets that do not match the user connection information are transferred to the uplink port, and RTP packets that match the user connection information are transferred back.

  The packet transfer apparatus includes, for example, a line interface having a plurality of access side connection ports for accommodating a plurality of IP phones and user terminals having a data communication function and an ISP side connection port for accommodating a GW apparatus installed on the ISP side, Protocol control unit, processor and communication processing program, device management table, user connection management table, etc. for performing transfer processing to the designated ISP side connection port and monitoring processing for session control packets for all packets received from the access side connection port A control unit that manages a memory that stores various management tables is provided. The packet transfer device monitors a session control packet from the SIP device terminal accommodated in the access side connection port, and transmits a session establishment request packet from the calling SIP device terminal to the communication destination SIP device terminal. If received, information that can identify the originating SIP device terminal and the terminating SIP device terminal from the message in the session establishment request packet is registered in the device management table. In addition, when a session establishment response packet is received from the destination SIP apparatus terminal, the apparatus management is performed based on information that can identify the calling side SIP apparatus terminal and the destination SIP apparatus terminal from the message in the session establishment response packet. When the table is searched and they match, the correspondence relationship of the calling SIP device terminal or the called SIP device terminal is registered in the device management table. After establishing a session between the originating SIP device terminal or the terminating SIP device terminal, the correspondence relationship is individually set in the user connection management table managed for each access side connection port that accommodates the originating or terminating SIP device terminal. Register information. When a packet is received from the access side connection port, the user connection management table is searched from the identification information of the received packet. If there is a mismatch, the forwarding to the ISP side connection port is performed. By performing the received packet transfer according to the above, the transfer delay time between the originating SIP device terminal and the terminating SIP device terminal is reduced.

According to the first solution of the present invention,
A first packet transfer device; a first packet transfer device; and a second packet transfer device that routes packets between a server or a network, wherein the first packet transfer device includes: A third port for communicating packets input from the first port for communicating with the second terminal and / or the second port for communicating with the second terminal with the second packet transfer apparatus And the second packet transfer device receives the packet and sends it back to the first packet transfer device. The first packet transfer device receives the packet from the second packet transfer device. In the first packet transfer device in the communication system that realizes communication between the first terminal and the second terminal by transferring according to the destination information,
Originating terminal information including identification information of the first terminal and identification information of the first port, and receiving terminal information including identification information of the second terminal and identification information of the second port A corresponding device management table,
A connection management table that stores output port information corresponding to the transmission source information and transmission destination information of the packet;
A processing unit,
The processor is
When the session establishment request packet from the first terminal is received via the first port, the identification information of the first terminal, the identification information of the first port in the session establishment request packet, Is registered in the originating terminal information of the device management table,
When a response packet from the second terminal to the session establishment request packet is received via the second port, the identification information of the second terminal in the response packet and the identification of the second port Information corresponding to the originating terminal information in the terminal information of the device management table,
The identification information of the first terminal registered in the device management table as transmission source information, the identification information of the second terminal as transmission destination information, and the second port information as output destination port information, Register in the connection management table,
The identification information of the second terminal registered in the device management table as transmission source information, the identification information of the first terminal as transmission destination information, and the first port information as output destination port information, Register in the connection management table,
When a packet is received from the first or second port, the connection management table is searched based on the transmission source information and transmission destination information of the received packet, and the second or first port is searched according to the corresponding output port information. The packet transfer device is provided for transferring a received packet through a port.

According to the second solution of the present invention,
A plurality of the above packet transfer devices are provided,
A communication system is provided in which each packet transfer apparatus is connected in multiple stages, and at least one of the plurality of packet transfer apparatuses is connected to the second packet transfer apparatus.

According to the present invention, in view of the above points, a packet transfer apparatus that prevents a voice data transfer delay when a voice call is made between terminal apparatuses connected to a packet transfer apparatus set up in an uplink VLAN in the same domain. Can be provided. Further, according to the present invention, it is possible to prevent quality deterioration due to transfer delay of audio data. According to the present invention, it is possible to achieve both security ensuring by applying an uplink VLAN and reduction in transfer delay.
According to the present invention, since it is possible to register the correspondence between the connection port and the information that can identify the terminal device from the SIP message in the session establishment process, between the terminal devices connected to the same packet transfer device, RTP communication via a loopback virtual communication path in the packet transfer apparatus is possible. In addition, according to the present invention, a reduction in packet transfer delay time can be realized. In addition, according to the present invention, it is possible to transfer with priority on RTP communication by registering priorities of different protocols in the table.

  FIG. 1 is a configuration diagram of a communication system according to the present embodiment. The communication system includes a packet transfer device (first packet transfer device) (1), an L3SW (Layer 3 switch, layer 3 switch, second packet transfer device) (2), a SIP server (3), SIP device terminal (5). The communication system may further include a WEB server (4) and a WEB host (6).

  In FIG. 1, a packet transfer apparatus (1) has a SIP snooping function, which will be described later, and constitutes a wide area L2 switch network (public access network). The public access network accommodates a WEB host (6), SIP device terminals (5-1, 5-2, 5-3, 5-4) and a WEB server (4). In order for the SIP device terminal (5) connected to the public access network to access the SIP server (3) accommodated in the ISP network, the L3SW (2) is connected between the public access network and the ISP network. Yes. An example of communication between the terminal devices shown in FIG. 1 will be described below.

  For example, when the WEB host (6) communicates with the WEB server (4), the packet is transferred to L3SW (2) by the uplink VLAN setting of the packet transfer apparatuses (1-1) and (1-3). By being routed back by the L3SW (2), the packet is transmitted to the WEB server (4) via the packet transfer apparatuses (1-3) and (1-2), and the WEB host (6) and the WEB server (4) ) Communication is possible.

  For example, when VoIP communication is performed between the SIP device terminal (5-1) having the identification name “UserB” and the SIP device terminal (5-2) having the identification name “UserC”, a normal uplink VLAN is used. In the set system, the packet from UserB is transferred to L3SW (2), routed back by L3SW (2), and received by UserC. In the present embodiment, the packet transfer apparatus (1-1) having the SIP snooping function allows RTP communication after session establishment between terminal apparatuses to be communicated by return transfer in the packet transfer apparatus (1-1). It becomes.

  For example, when VoIP communication across L2SW is performed between a SIP device terminal (5-3) having the identification name “UserD” and a SIP device terminal (5-4) having the identification name “UserE”, this implementation is performed. In the embodiment, the packet transfer apparatus (1-3) having the SIP snooping function enables RTP communication after session establishment between the terminal apparatuses to be performed by return transfer in the packet transfer apparatus (1-3). .

FIG. 2 is a diagram illustrating an example of a communication network to which the packet transfer apparatus is applied. FIG. 2 is also a simplified illustration of the configuration of FIG.
In the configuration of FIG. 2, between the SIP device terminal (5-1) having the identification name “UserB” accommodated in the public access network and the SIP device terminal (5-2) having the identification name “UserC”, The operation of the packet transfer apparatus (1) of the present embodiment will be described by taking as an example a case where a session is established via the packet transfer apparatus (1), L3SW (2), and SIP server (3) and VoIP communication is performed. To do.

  In this example, the IP address and URI (Uniform Resource Identifier) of the SIP device terminal (first terminal) (5-1) on the calling side are set to, for example, “100.100.1.1” and “userb. aaaa.com ". Further, the IP address and URI of the SIP device terminal (second terminal) (5-2) on the called side are, for example, “100.1000.1.10” and “userc.aaa.com”, respectively. The IP address and URI of the SIP server (3) accommodated in the ISP network are, for example, “138.855.28.1” and “aaa.com”. The SIP device terminal (5-1) of UserB is connected to port 1 (first port) of the packet transfer device (1), and the SIP device terminal (5-2) of UserC is connected to port 2 (second port). ) And L3SW (2) is connected to port n (third port). Each port may be connected via another packet transfer apparatus or the like in addition to being directly connected to the terminal and the L3SW.

FIG. 3 is a block diagram showing an example of the configuration of the packet transfer apparatus (1).
The packet transfer apparatus (1) includes a plurality of input / output line interface (20-1 to 20-n: n is a natural number), an input / output line (10-1 to 10-n: n is a natural number), a protocol It has a processing unit (30) and a control unit (40) for controlling them. Control by the control terminal (120) is also possible. A plurality of port numbers are assigned to the input / output lines (10-1 to 10-n).

  The control unit (120) includes a memory (50) that stores the processing program (60, 100) and each table (70, 80, 90), and a processor (processing unit) (110) that executes the processing program (60, 100). ). The memory (50) includes packet transfer control (60) and snooping control message processing (100) as processing programs executed by the processor (110). The packet transfer control (60) analyzes the received packet from the line interface (20), and outputs the packet according to the port management table (80) for managing the MAC address and the user connection management table (90) held for each port. Forward to port. In the snooping control message processing (100), when the received packet from the line interface (20) includes a SIP message for session control between the SIP device terminals (5), the IP specifying the SIP device terminal (5) from the SIP payload. A device management table (70) and a user connection management table (90) for snooping addresses and port numbers and managing them are handled.

  One of the features of this embodiment is that, when an RTP packet is received from the line interface (20), user connection management in which an IP address and a port number for identifying the SIP device terminal (5) are associated in the session connection process. According to the table (90), the packet transfer device (1) can transfer the RTP packet in a loopback manner. On the other hand, for example, a packet from a terminal for which a session is not established is transferred to the uplink according to the uplink VLAN setting, so that, for example, a broadcast packet is prevented from being transferred to another terminal, and security is ensured.

FIG. 4 shows the packet format of communicated SIP messages for session establishment and disconnection.
The SIP message is set in the IP header (131), the TCP / UDP header (132), and the payload part (133) of the IP packet. The SIP message includes a start line (Start-line) (134) indicating the type and destination of the SIP message, a message header (Message-header) (135) including SIP parameters, and a connection logically formed between the terminals. Message body (Message-body) (136) in which information is described. Specific contents of the SIP message will be described later with reference to FIGS. 12 to 23 based on the header field defined in RFC3261.

8 and 9 are table configuration diagrams of the device management table (70) and the user connection management table (90).
As shown in FIG. 8, the device management table (70) includes one or a plurality of entries (EN) indicating the relationship between the originating device terminal information (70A) and the terminating device terminal information (70B). The originating device terminal information includes, for example, a request source identifier, an originating IP address, a data reception port number, and device port information. The called-side device terminal information includes, for example, a called-side IP address, a data reception port number, and device port information.

  As shown in FIG. 8, the user connection management table (90) includes, for each port, a destination address (Destination Address), a source address (Source Address), a destination port number (for determining an output destination port). (Destination Port), a source port number (Source Port), output destination port information, and one or a plurality of entries (EN) indicating a correspondence relationship between priorities. FIG. 8 shows a table configuration example of port 1 and port 2. The priorities are for transferring packets to be preferentially output by giving priorities to various protocols. Assume that the packet transfer apparatus (1) sets the output destination port for all received packets fixedly in advance to the uplink port (port n) to which the upper L3SW is connected. In this embodiment, a user connection management table is provided for each port, but it may be configured by one or an appropriate number of tables.

Hereinafter, referring to the sequence diagrams shown in FIGS. 5 to 7, the device management table (70) and the user connection management table (90) shown in FIGS. 8 and 9, the SIP device accommodated in the public access network The operation of the packet transfer device (1) and the like when performing VoIP communication between the terminals (5) will be described.
FIG. 5 is a diagram showing a session establishment sequence between the originating SIP device terminal (5-1) and the terminating SIP device terminal (5-2) in the public access network of FIG. First, the sequence of session establishment and information registration in the table will be described with reference to FIG.

  Prior to the RTP communication with the called-side SIP device terminal (5-2), the calling-side SIP device terminal (5-1) sends an INVITE including a SIP message for session establishment request to the SIP server (3). A packet (session establishment request packet) M1 is transmitted (101). For example, as shown in FIG. 12, the INVITE packet M1 includes the IP address of the SIP server (3) as the destination address (DA) of the IP header and the originating SIP device terminal (5-1) as the source address (SA). And the port number “5060” for SIP is included in the UDP header. In the figure, the character string following the # symbol is attached for annotation.

  The SIP message includes the message type “INVITE” and the URI of the called SIP device terminal (5-2) on the start line (134). In the message header part (135), the URI and port number of the calling SIP device terminal (5-1) are designated by the Via header indicating the message path, the request destination identifier is designated by the To header, the request source identifier is designated by the From header, and Call. -Each session identifier is specified by ID. In the message body (136), the IP address of the originating SIP device terminal (5-1) is designated by the c parameter, and the port number for data reception in the originating SIP device terminal (5-1) is designated by the m parameter. 50050 "is designated.

The INVITE packet M1 is received at port 1 of the packet transfer apparatus (1). When receiving the INVITE packet M1, the packet transfer apparatus (1) determines that the received packet is for the SIP message from the value “5060” of the UDP port number. For example, it can be determined that the packet is an INVITE packet by referring to the start line of the SIP message. Further, the packet transfer device (1) receives the IP address “100.100.1.1” and the data for specifying the originating SIP device terminal (5-1) based on the information in the received INVITE packet. The information indicating the correspondence between the port number “50050” for use and the identification information of the device port (port 1) that received the packet is registered in the device management table (70) (102). The IP address and the data reception port number can be extracted from, for example, the c parameter and the m parameter. Besides this, it may be extracted from appropriate information in the SIP message. Further, the packet transfer apparatus (1) may further register a request source identifier from the From header. One of the entries in the device management table (70) is, for example, in the state shown in FIG. The packet transfer device (1) transfers the packet to the uplink port (port n) according to the user connection management table (90) of the device port (port 1).
Upon receiving the INVITE packet M2 (103), the L3SW (2) transmits the INVITE packet M3 to the SIP server (3) according to the routing table (104). The configuration of the packets M2 and M3 can be the same as that of the packet M1. In the description of the present embodiment, each packet is represented by Mx. However, in the following description, headers and the like are appropriately added / changed / deleted for packets transferred by the packet transfer device (1) and the L3SW (2). In addition, the same configuration can be adopted.

  When the SIP server (3) receives the INVITE packet M3, the SIP server terminal (3) performs a predetermined database and / or predetermined processing based on the destination identifier “UserC@aaa.com” indicated by the start line of the SIP message. The IP address “100.100.1.10.” Of 5-2) is specified. For example, as shown in FIG. 13, the SIP server (3) adds a new Via header for adding its own server to the message path to the message header, and rewrites the destination address and the source address of the packet M3. The packet M4 is created and transferred to the destination SIP device terminal (5-2) (105). When the L3SW (2) receives the INVITE packet M4 (105), it transmits the INVITE packet M5 to the destination SIP device terminal (5-2) according to the routing table (106). When the packet transfer device (1) receives the INVITE packet M5 via the port n, it determines an output destination port from the port management table (80) managing the MAC address information, and sends the INVITE packet M6 to the destination SIP. Transfer to the device terminal (5-2) (107).

  When the incoming SIP device terminal (5-2) responds to the incoming call, a 200 OK packet M7 including an SIP response message is transmitted to the SIP server (3) (108). For example, as shown in FIG. 14, the 200 OK packet M7 indicates the message type “200 OK” on the start line of the SIP message, and includes the same information as the INVITE packet M6 in the message header portion. In the message body, the IP address of the destination SIP device terminal (5-2) is designated by the c parameter, and the port number “50070” for data reception at the destination SIP device terminal (5-2) is designated by the m parameter. It is specified.

  The 200 OK packet M7 is received at port 2 of the packet transfer apparatus (1). When receiving the 200 OK packet M7, the packet transfer apparatus (1) determines that the received packet is for the SIP message from the value “5060” of the UDP port number. Further, since Cseq (201) of the SIP message is “INVITE”, it is determined that it is 200 OK for the INVITE packet. The packet transfer device (1) snoops (or refers to or extracts) the request source identifier indicated by the From header of the message header, and requests the source device terminal information (70A) registered in the device management table (70). Determine if it matches the identifier.

  When the packet transfer device (1) matches, the IP address “100.1000.1.10” and the port for identifying the called-side SIP device terminal UserC (5-2) in the called-side device terminal information (70B) The number “50070” is extracted from the c and m parameters of the packet M7, and is registered in EN1 of the device management table (70) in association with the identification information of the device port (port 2) that received the packet (109). Also, EN2 is registered in the user connection management table (90-1) of the device port (port 1), and EN2 is registered in the user connection management table (90-2) of the device port (port 2). For example, EN1 of the device management table (70) is in the state shown in FIG.

  Specifically, the packet transfer device (1) stores in the user connection management table (90-1) corresponding to the device port (here, port 1) of the originating side device terminal information stored in the device management table (70). A new entry (EN2) is registered. For example, the packet transfer device (1) sets the IP address, port number, and device port (port 2 in this case) of the destination device terminal information registered in the device management table (70) to the user connection management table (90-). Stored in the destination address, destination port and output port fields of 1). Further, the packet transfer device (1) uses the IP address and port number of the source device terminal information registered in the device management table (70) as the source address and source of the user connection management table (90-1), respectively. Store in the port column. The packet transfer apparatus (1) sets the priority of the registered entry to “high”, for example.

  Further, the packet transfer device (1) adds a new one to the user connection management table (90-2) corresponding to the device port (port 2 in this case) of the destination device terminal information stored in the device management table (70). An entry (EN2) is registered. The user connection management table (90-1) is registered so that the destination and the transmission source are reversed so that the packet received from the port 2 is also transferred back. For example, the packet transfer apparatus (1) uses the IP address, port number, and apparatus port (here, port 1) of the originating apparatus terminal information as the destination address, destination port, and output of the user connection management table (90-2), respectively. Store in the port column. Further, the packet transfer device (1) stores the IP address and port number of the destination device terminal information in the source address and source port fields of the user connection management table (90-2), respectively. The packet transfer apparatus (1) sets the priority of the registered entry to “high”, for example.

  On the other hand, in the packet transfer device (1), the request source identifier indicated by the From header of the message header of the packet M7 matches the request source identifier of the source device terminal information (70A) registered in the device management table (70). If not, the 200 OK packet M8 is transferred to the uplink port according to EN1 of the user connection management table (90-1) (110). When the L3SW (2) receives the 200 OK packet M8, the L3SW (2) transmits the 200 OK packet M9 to the SIP server (3) according to the routing table (111).

  When the SIP server (3) receives the 200 OK packet M9, for example, as shown in FIG. 15, the Via header for the SIP server (3) is deleted from the message header portion, and the destination IP address and the transmission source of the IP header are deleted. A 200 OK packet M10 addressed to the originating SIP device terminal (5-1) with the rewritten IP address is transmitted (112). When the L3SW (2) receives the 200 OK packet M10, the L3SW (2) transmits the 200 OK packet M11 to the originating SIP device terminal (5-1) according to the routing table (113). When the packet transfer device (1) receives the 200 OK packet M11, the packet transfer device (1) determines an output destination port from the port management table managing the MAC address information, and sends the 200 OK packet M12 to the originating SIP device terminal (5-1). (114).

  When the originating SIP device terminal (5-1) receives the 200 OK packet M12, for example, it transmits an ACK packet M13 shown in FIG. 16 (115). The ACK packet M13 is received by the packet transfer device (1). When receiving the ACK packet M13, the packet transfer apparatus (1) determines that the received packet is for the SIP message from the value “5060” of the UDP port number, and the message type is “ACK” at the start line of the SIP message. Therefore, the ACK packet M14 is transferred to the uplink port (116). When the L3SW (2) receives the ACK packet M14, the L3SW (2) transmits the ACK packet M15 to the SIP server according to the routing table (117).

  When the SIP server (3) receives the ACK packet M15, the SIP server terminal (5-2) receives the IP address “100.100” from the destination identifier “UserC@aaa.com” indicated by the start line or To header of the SIP message. “100.1.10” is specified. For example, as shown in FIG. 17, the SIP server (3) adds a new Via header for adding its own server to the message path in the message header, and rewrites the destination address and the source address of the packet M15. The packet M16 is transferred to the destination SIP device terminal (5-2) (118). When the L3SW (2) receives the ACK packet M16, the L3SW (2) transmits the ACK packet M17 to the destination SIP device terminal (5-2) according to the routing table (119).

When the packet transfer device (1) receives the ACK packet M17, it determines an output destination port from the port management table (80) that manages the MAC address information, and uses it as the ACK packet M18 as the destination SIP device terminal (5- 2) (120).
FIG. 6 is a diagram showing an RTP packet transfer sequence by the packet transfer apparatus according to the present embodiment. Next, a transfer sequence of RTP packets such as voice data between the calling-side SIP device terminal (5-1) and the called-side SIP device terminal (5-2) will be described with reference to FIG.

For example, as shown in FIG. 18, the calling-side SIP device terminal (5-1) has a destination IP address with the IP address “100.1000.1.10” of the called-side SIP device terminal (5-2), a UDP destination. The RTP packet D1 including the port “50070” is transmitted (201).
When the packet transfer apparatus (1) receives the RTP packet D1 from the port 1, the packet transfer apparatus (1) corresponds to the destination IP address “100.100.1.10” of the packet D1 from the user connection management table (port 1) (90-1). Search for the entry you want. Here, high priority EN2 is selected. The packet transfer device (1) checks the received packet according to the registration information of the corresponding entry. In this case, since the source IP address “100.100.1.1”, the destination port number “50070”, and the source port number “50050” of the RTP packet D1 satisfy the registration conditions indicated by the entry EN2, the packet In accordance with the output port information, the transfer device (1) loops back and transfers the RTP packet D2 to the destination SIP device terminal (5-2) via the port 2 (202).

On the other hand, the destination SIP device terminal (5-2), for example, as shown in FIG. 19, the IP address “100.100.1.1” of the calling party SIP device terminal (5-1) as the destination IP address, The RTP packet D3 including the UDP destination port number “50050” is transmitted (203).
When the packet transfer apparatus (1) receives the RTP packet D3 from the port 2, it corresponds to the destination IP address “100.100.1.1” of the packet D3 from the user connection management table (port 2) (90-2). Search for the entry you want. Here, high priority EN2 is selected. The packet transfer device (1) checks the received packet according to the registration information of the corresponding entry. In this case, the source IP address “100.100.1.10”, the destination port number “50050”, and the source port number “50070” of the RTP packet D3 satisfy the registration condition indicated by the entry EN2, and thus the packet In accordance with the output port information, the transfer device (1) loops back and transfers the RTP packet D4 to the originating SIP device terminal (5-1) via the port 1 (204). Packets other than those between the originating SIP device terminal (5-1) and the terminating SIP device terminal (5-2) are stored in the user connection management table (port 1) (90-1) and the user connection management table (port 2). ) Since it corresponds to the entry EN1 of (90-2), it is transferred to the uplink port.

FIG. 7 is a diagram showing a session disconnection sequence between the originating SIP device terminal (5-1) and the terminating SIP device terminal (5-2). Next, with reference to FIG. 7, the sequence of session disconnection and information deletion from the table will be described.
For example, when the user of the originating SIP device terminal (5-1) disconnects the session, the BYE packet M19 including the SIP message for session disconnection is transmitted from the originating SIP device terminal (5-1) ( 301). The BYE packet M19 in this case has, for example, the same IP header and UDP header as the ACK packet M13 as shown in FIG. 20, and the message type “BYE” and the destination SIP device are included in the start line of the SIP message. The IP address “100.100.1.10.” Of the terminal (5-2) is included. When the packet transfer apparatus (1) receives the BYE packet M19 from the port 1, the packet transfer apparatus (1) determines that the received packet is for the SIP message from the UDP port number. In addition, the packet transfer apparatus 1 snoops the request source identifier indicated by the From header of the message header, and determines whether or not it matches the request source identifier of the source apparatus terminal information (70A) registered in the apparatus management table (70). To do. If they match, the entry EN1 is deleted, and EN2 in the user connection management table (port 1) (90-1) and EN2 in the user connection management table (port 2) are deleted (302). Which entry in the user connection management table (90-1) or (90-2) is to be deleted can be specified based on, for example, information stored in entry 1 of the device management table (70). The packet transfer apparatus (1) transfers the BYE packet M20 to the uplink port according to EN1 of the user connection management table (port 1) (303).

  On the other hand, when the request source identifier indicated by the From header of the message header does not match the request source identifier of the source device terminal information (70A) registered in the device management table (70), for example, the user connection management table (port In accordance with EN1 of 1), the BYE packet M20 is transferred to the uplink port (303). When the L3SW (2) receives the BYE packet M20, the L3SW (2) transmits the BYE packet M21 to the SIP server according to the routing table (304).

  When the SIP server (3) receives the BYE packet M21, the SIP server terminal (5-2) receives the IP address “100.2” from the destination identifier “UserC@aaa.com” indicated by the start line or To header of the SIP message. “100.1.10” is specified. Further, for example, as shown in FIG. 21, the SIP server (3) adds a new Via header for adding the server to the message path to the message header, and sets the destination address and the source address of the BYE packet M21. The rewritten BYE packet M22 is transferred to the destination SIP device terminal (5-2) (305). When the L3SW (2) receives the BYE packet M22, the L3SW (2) transmits the BYE packet M23 to the destination SIP apparatus terminal (5-2) according to the routing table (306). When the packet transfer apparatus (1) receives the BYE packet M23 via the port n, the packet transfer apparatus (1) determines the output destination port from the port management table (80) managing the MAC address information, and sends the BYE packet M24 to the destination side. Transfer to the SIP device terminal (5-2) (307).

  Upon receiving the BYE packet M24, the terminating SIP device terminal (5-2) transmits a 200 OK packet M25 including a SIP response message to the SIP server (3) (308). For example, as shown in FIG. 22, the 200 OK packet M25 indicates the message type “200 OK” on the start line of the SIP message, and includes the same information as the BYE packet M24 in the message header portion.

  The 200 OK packet M25 is received at port 2 of the packet transfer apparatus (1). When receiving the 200 OK packet M25, the packet transfer apparatus (1) determines that the received packet is for the SIP message from the value “5060” of the UDP port number, and Cseq (202) of the SIP message is “BYE”. Therefore, it is determined that it is 200 OK for the BYE packet, and the 200 OK packet M26 is transferred to the uplink port (309). When the L3SW (2) receives the 200 OK packet M26, the L3SW (2) transmits the 200 OK packet M27 to the SIP server according to the routing table (310).

  When the SIP server (3) receives the 200 OK packet M27, for example, as shown in FIG. 23, the Via header for the SIP server (3) is deleted from the message header portion, and the destination IP address and the transmission source of the IP header are deleted. A 200 OK packet M28 addressed to the originating SIP device terminal (5-1) with the rewritten IP address is transmitted (311). When the L3SW (2) receives the 200 OK packet M28, the L3SW (2) transmits the 200 OK packet M29 to the originating SIP device terminal (5-1) according to the routing table (312). When the packet transfer device (1) receives the 200 OK packet M29 via the port n, it determines the output destination port from the port management table (80) that manages the MAC address information, and outputs it as a 200 OK packet M30. Transfer to the side SIP device terminal (5-1) (313).

  FIG. 10 shows a flowchart of the packet transfer control program (60) necessary for realizing the return transfer in the packet transfer apparatus (1) described above. For example, the processor (110) of the control unit (40) can read and execute the following processing from the packet transfer control program (60) stored in the memory (50).

In the packet transfer control program (60), the received packet is read from the protocol processing unit (30), and if the reception route is reception from the terminal connection port (S61), it is determined whether the received packet is for a SIP message. (S62). If it is a SIP packet (S62), snooping control message processing is executed (S100). Details of the processing will be described later. On the other hand, if the received packet is not a SIP packet (S62), the user connection management table (90) is searched for an entry corresponding to the destination IP address. If there is a corresponding entry in the user connection management table (90), the source IP address, the destination port number, and the source port number are determined, and the output destination port is determined (S63). If there is no corresponding entry, a statically set uplink port is determined as an output destination port (S63). If the output destination port is determined, the received packet is transferred to the output port (S66).
On the other hand, if the reception route is reception from the uplink port (S61), the output destination port is determined from the port management table (80) managing the MAC address information (S65), and if the output destination port is determined, The received packet is transferred to the output port (S66).

FIG. 11 shows the details of the snooping control message processing (100).
In the snooping control message process (100), the message type of the SIP message included in the received packet is determined (S101).
For example, when the received message is an INVITE message (S101), the packet transfer apparatus (1) sends the source IP address, the source port number specified in the message header of the SIP message, and the connection port number. The side device terminal information is registered as an entry in the device management table (70) (S102).
If the received message is a 200 OK packet M25 (S101), if the method name of Cseq (Command sequence) specified in the message header of the SIP message is INVITE (201), it is a 200 OK message for the INVITE message. Judgment is made and the process of step S103 is executed. For example, the packet transfer apparatus (1) registers an entry in the apparatus management table (70) for the called-side apparatus terminal information in which the called-side IP address, the called-side port number and the connection port number are associated (S103). Further, in the user connection management table (90) held for each connection port, the relationship among the destination address, the source address, the destination port number, the source port number, the output destination port, and the priority for determining the output destination port Is registered (S103).
For example, when the received message is a BYE message (S101), the entry having the request source identifier specified in the message header of the SIP message is deleted from the device management table (70), and the entry of the related user connection management table is deleted. Delete (S104).
If the received message is 200 OK for BYE, or another message or packet (S101), the process proceeds to the next process (S63).

(Example of processing in a multi-stage configuration)
In the above description, the example in which the terminals (5-1) and (5-2) are connected to one packet transfer device (1) has been described. For example, as shown in FIG. Even when connected to the network, each packet transfer apparatus operates as described above, so that the packet transfer apparatus can perform return transfer.

In the following, processing when two stages are connected as shown in FIG. 1 will be described. In this example, for convenience of explanation, the originating SIP device terminal (5-1) is connected to port 1 of the packet forwarding device (1-1), and the terminating SIP device terminal (5-2) is connected to the packet forwarding device (1). -2) is assumed to be connected to port 2 (for example, the position of UserE). In this example, port 1 of the packet transfer device (1-3) is connected to the packet transfer device (1-1), port 2 is connected to the packet transfer device (1-3), and port n is connected to L3SW (2). It is assumed that
24 and 25 are examples of a device management table (70) and a user connection management table (90) in each packet transfer device connected in multiple stages.

  The INVITE packet from the originating SIP device terminal (5-1) is received at port 1 of the packet transfer device (1-1). The packet transfer device (1-1), like the processing 102 described above, has the IP address “100.100.1.1” of the originating SIP device terminal (5-1) and the data reception port number “50050”. And information indicating the correspondence between the identification information of the device port (port 1) that received the packet is registered in the originating device terminal information of the device management table (70). FIG. 24A shows an example of a device management table of the packet transfer device (1-1). The packet transfer apparatus (1-1) transfers the INVITE packet to the packet transfer apparatus (1-3) via the uplink port n.

  The packet transfer apparatus (1-3) receives the INVITE packet at the port 1, and receives the IP address of the originating SIP apparatus terminal (5-1), the port number for data reception, and the packet reception in the same manner as the processing 102 described above. The device port (port 1) identification information is registered in the source device terminal information of the device management table (70). FIG. 25A shows an example of a device management table of the packet transfer device (1-3). The INVITE packet is received by the destination SIP device terminal (5-2) via the SIP server in the same manner as described above.

  The called-side SIP device terminal (5-2) transmits a 200 OK packet including the SIP response message to the SIP server (3) in the same manner as the processing 108 described above. The 200 OK packet is received at port 2 of the packet transfer apparatus (1-2). The packet transfer device (1-2) snoops the request source identifier indicated by the From header of the message header, and matches the request source identifier of the source device terminal information (70A) registered in the device management table (70). Judge. Here, since the originating device terminal information is not registered in the device management table (70) of the packet transfer device (1-2) as shown in FIG. 24 (b), the 200 OK packet is transmitted via the port n. To the packet transfer device (1-3).

  The 200 OK packet is received at port 2 of the packet transfer apparatus (1-3). The packet transfer device (1-3) snoops the request source identifier indicated by the From header of the message header, and matches the request source identifier of the source device terminal information (70A) registered in the device management table (70). Judge. Here, as shown in FIG. 25 (a), since there is the originating side device terminal information with the matching request source identifier, the packet forwarding device (1-3), like the processing 109 described above, In the information (70B), the IP address of the destination SIP device terminal (5-2), the port number, and the identification information of the device port (port 2) that received the packet are registered in EN1 of the device management table (70) ( FIG. 25 (b)). Further, since the packet transmission device (1-3) has the source device terminal information (70A) and the destination device terminal information (70B) registered in the device management table (70), each information ( 70A) and (70B) are registered in the user connection management tables (90-1) and (90-2) (FIGS. 25 (c) and (d)).

On the other hand, since the packet transfer apparatus (1-1) does not receive the 200 OK packet for the INVITE packet from the port on the terminal side, the apparatus management table (70) remains as shown in FIG. Since the receiving-side device terminal information (70B) is not registered, new information is not registered in the user connection management table.
As described above, since information is not registered in the user connection management table in the packet transfer apparatuses (1-1) and (1-2), packets received from the ports 1 and 2 on the terminal side according to the uplink VLAN setting are Forwarded to uplink port n. On the other hand, in the packet transfer apparatus (1-3), since information is registered in the user management table as shown in FIGS. 25 (c) and 25 (d), the originating SIP apparatus terminal (5-1) and the terminating SIP are registered. Packets between the device terminals (5-2) can be transferred back by the packet transfer device (1-3) for communication.
As described above, it is possible to configure a multi-stage connected network using packet transfer apparatuses having similar operation programs.

(Network configuration example)
FIG. 26 shows an example of VoIP communication in a wide area L2 switch network (public access network) in which the packet transfer apparatus (1) having the snooping function described above is configured in multiple stages.
Considering the entire network, since it can be transferred back in the lower network, it is effective in reducing the traffic resources and transfer delay time of the entire network and releasing congestion of the L3SW (2).

  The present invention can be used, for example, in a communication system in which an uplink VLAN is set. In addition, the present invention can be used for, for example, access networks constituting the same domain.

The block diagram of the communication system of this Embodiment. The figure which shows an example of the communication network to which the packet transfer apparatus of this Embodiment is applied. The figure which shows the structure of the packet transfer apparatus of this Embodiment. The figure which shows the packet format of a SIP message. The figure which shows the session establishment sequence between the originating side SIP apparatus terminal (5-1) and the destination side SIP apparatus terminal (5-2) in the public access network of FIG. The figure which shows the transfer sequence of the RTP packet by the packet transfer apparatus of this Embodiment. The figure which shows the session cutting | disconnection sequence between an origination side SIP apparatus terminal (5-1) and an arrival side SIP apparatus terminal (5-2). The figure which shows the content of the apparatus management table (70) with which the packet transfer apparatus of this Embodiment is provided, and a user connection management table (90) (FIG. 5: Table registration 1). The figure which shows the content of the apparatus management table (70) with which the packet transfer apparatus of this Embodiment is provided, and a user connection management table (90) (FIG. 5: Table registration 2). The flowchart of a packet transfer control program (60). The flowchart of a SIP snooping control message processing program (100). The figure which shows one example of the INVITE packet M1 in FIG. The figure which shows an example of the INVITE packet M4 in FIG. The figure which shows an example of the 200 OK packet M7 in FIG. The figure which shows one example of the 200 OK packet M10 in FIG. The figure which shows one example of the ACK packet M13 in FIG. The figure which shows one example of the ACK packet M16 in FIG. The figure which shows one example of the RTP packet D1 in FIG. The figure which shows one example of the RTP packet D3 in FIG.

The figure which shows an example of the BYE packet M19 in FIG. The figure which shows one example of the BYE packet M22 in FIG. The figure which shows one example of the 200 OK packet M25 in FIG. The figure which shows an example of the 200 OK packet M28 in FIG. The figure which shows the example (1) of the apparatus management table (70) and user connection management table (90) in each packet transfer apparatus connected in multistage. The figure which shows the example (2) of the apparatus management table (70) and user connection management table (90) in each packet transfer apparatus connected in multistage. The figure which shows an example of the communication network to which the packet transfer apparatus of this invention is applied to a large-scale network.

Explanation of symbols

1 Packet transfer device 2 L3SW
3 SIP server 4 WEB server 5 SIP device terminal 6 WEB host 10 device port 20 line interface 30 protocol processing unit 40 control unit 50 memory 60 packet transfer control program 70 device management table 80 port management table 90 user connection management table 100 snooping control message Processing program 110 Processor 120 Controller

Claims (8)

A first packet transfer device; a first packet transfer device; and a second packet transfer device that routes packets between a server or a network, wherein the first packet transfer device includes: A third port for communicating packets input from the first port for communicating with the second terminal and / or the second port for communicating with the second terminal with the second packet transfer apparatus And the second packet transfer device receives the packet and sends it back to the first packet transfer device. The first packet transfer device receives the packet from the second packet transfer device. In the first packet transfer device in the communication system that realizes communication between the first terminal and the second terminal by transferring according to the destination information,
Originating terminal information including identification information of the first terminal and identification information of the first port, and receiving terminal information including identification information of the second terminal and identification information of the second port A corresponding device management table,
A connection management table that stores output port information corresponding to the transmission source information and transmission destination information of the packet;
A processing unit,
The processor is
When the session establishment request packet from the first terminal is received via the first port, the identification information of the first terminal, the identification information of the first port in the session establishment request packet, Is registered in the originating terminal information of the device management table,
When a response packet from the second terminal to the session establishment request packet is received via the second port, the identification information of the second terminal in the response packet and the identification of the second port Information corresponding to the originating terminal information in the terminal information of the device management table,
The identification information of the first terminal registered in the device management table as transmission source information, the identification information of the second terminal as transmission destination information, and the second port information as output destination port information, Register in the connection management table,
The identification information of the second terminal registered in the device management table as transmission source information, the identification information of the first terminal as transmission destination information, and the first port information as output destination port information, Register in the connection management table,
When a packet is received from the first or second port, the connection management table is searched based on the transmission source information and transmission destination information of the received packet, and the second or first port is searched according to the corresponding output port information. The packet transfer apparatus which transfers a received packet via a port. The processor is
When the source information and destination information of the received packet are not registered in the connection management table, or when the output port information of the connection management table indicates a third port, The packet transfer apparatus according to claim 1, wherein the received packet is transferred to the second packet transfer apparatus. The originating terminal information registered in the device management table includes one or more of an IP address of the first terminal, a UDP port number, and a number of the first port. Including one or more of the IP address of the second terminal, the UDP port number, and the second port number;
The processor is
The IP address of the first terminal in the session establishment request packet, the UDP port number, and the number of the first port that has received the session establishment request packet are stored in the originating terminal information of the device management table. Register,
The IP address of the second terminal in the response packet to the session establishment request packet, the UDP port number, and the number of the second port that has received the response packet are used as destination terminal information in the device management table. The packet transfer apparatus according to claim 1, registered in   Information registered in the connection management table includes a destination IP address, a source IP address, a UDP destination port number, and a UDP source port number of a packet received via the first or second port. The packet transfer apparatus according to claim 1, comprising any one or a plurality of output port numbers.   When a session disconnection request packet is received from the first or second terminal, the source information and destination information of the connection management table are searched based on the identification information of the source of the received packet, and the matching entry is deleted And searching for the identification information of the first terminal and the identification information of the second terminal in the device management table based on the identification information of the transmission source of the received packet, and deleting the matching entry. Packet transfer device. SIP protocol is used as a protocol for session control,
An INVITE packet as the session establishment request packet, a 200 OK packet for the INVITE packet as the response packet, and a BYE message as the session disconnection request packet are respectively snooped,
The packet transfer apparatus according to claim 1, wherein the snooping information is registered in the apparatus management table and the connection management table. Further register the priority in the connection management table,
In the first and second ports, when congestion occurs between the packet transferred from the second or the first port and the packet transferred from the third port, according to the priority, The packet transfer apparatus according to claim 1, wherein a packet transferred from the second or first port is preferentially transferred. A plurality of the packet transfer devices according to claim 1,
A communication system in which each packet transfer apparatus is connected in multiple stages, and at least one of the plurality of packet transfer apparatuses is connected to the second packet transfer apparatus.

Images